This invention relates to high amperage plugs for use for example in connection with electric ranges, and more particularly with the manufacture into such plugs of its blades.
It is known in the prior art to manufacture range plugs by crimping into blade cups, bisected by planes perpendicular to planes of the blades, bundles of small-diameter conductors, and thereafter by hand twisting the crimped bundles into blade parallelism and inserting thereupon the blades into an injection die.
The prior art would also optionally incorporate into the plug a round ground pin, in which case cups, integral with the pins with bisectors in planes perpendicular to the pin axes, would have crimped thereinto groups of conductor wires, and each pin would be wiggled into a die hole in the same general overall intensively repetitive motions in which the blades were brought into alignment and fitted in their die holes.
Range blade thicknesses in the prior art were 0.095-0.105 inches in overall thickness, while ordinary household plug blades had thicknesses, overall, of 0.055 to 0.065 inches.
Blanche U.S. Pat. No. 5,662,484, xe2x80x9cBridged Electrical Plugxe2x80x9d, discloses a plug for smaller voltages in which are provided for crimping thereinto conductors three cups opening in parallel directions perpendicular to the longitudinal direction of the folded blades with which the cups are integral.
Bases with preformed halves, thermoplastically welded together, are known in the prior art.
We have discovered that such plugs may be better manufactured by reorienting the blade conductor contact surfaces so that in the novel blades each of the surfaces"" line generators is parallel with the bisector plane of its respective blade; by positioning the blades before securing thereinto the conductors; and by then securing the contact surfaces to their conductors.
In preferred embodiments, the cup bisectors are parallel with blade and pin bisectors, and blade thickness is achieved by centrally outwardly opposingly embossing integral pairs of blade portions.